We propose to investigate the use of hair for monitoring a person's body burden as related to exposure to toxic chemicals. This concept is based upon our previous work that demonstrated the retention of drugs or their metabolities in the hair in relation to their drug use histories. Analysis of hair samples for toxic chemicals would provide unique advantage over indirect monitoring methods currently employed in occupational health surveillance programs such as kidney function tests and chest X-rays. Thus, hair samples are readily accessible and could provide both short and long-term toxic chemical exposure histories long after the occurrance of such exposures. Our drug work employed analytical techniques sensitive to the low nanogram level that permitted analyses to be carried out on a single hair. Procedures were developed to readily distinguish external contaminants from metabolic incorporation of drugs in hair. Analytical results demonstrated not only that drugs on their metabolites were retained in users' hair, but that drug residues as a function of distance along the hair correlated well with drug use history. Methodology similar to that employed in the drug work will be utilized in this proposed study. Investigation into the suitability of hair as a monitor of exposure to toxic chemicals will be first studied using hair from mice injected with the chemicals of interest. The latter include selected halogenated hydrocarbons, including polychlorinated biphenyls, and hydrazines, which were chosen for study on the basis of their widespread use, their known toxicity or carcinogenicity, and the availability of highly sensitive techniques viz., gas chromatography with electron capture or mass spectrometric detection, and radioimmunoassay for their analysis. Upon completion of the experiments with mice, human hair samples from occupational workers will be examined with an eye to providing a unique capability to determine the etiology of toxic symptoms in persons dealing with hazardous chemicals.